Field of the Invention
This invention relates to a process for preparing spandex filaments in which a solution of the polymer contains a tertiary amine stabilizer and titanium dioxide particles. In particular, the invention concerns improvements in such a process wherein the addition of an organic base to the solution results in improved processing and product yields.
Description of the Prior Art
Spandex filaments are well known and have found considerable utility and commercial success in a large variety of fabrics. Many processes have been disclosed for the manufacture of spandex filaments from solutions of spandex polymer. Dry spinning is used extensively.
The need for special stabilizers and other agents in spandex filaments has led to inclusion of various organic and inorganic compounds in the filaments. Additives, such as fillers, pigments, plasticizers and stabilizers against degradation by oxygen, chlorine, heat, fumes or ultra-violet light, are often incorporated into the filaments by being added to the polymer solution prior to spinning. In the polymer solution, the additives may dissolve or form a slurry.
Hunt, U.S. Pat. No. 3,428,711, the entire disclosure of which is hereby incorporated by reference, describes polymeric tertiary-aminoalkyl acrylates and methacrylates, which are particularly suited for use as stabilizers and/or dye enhancers for spandex fibers. Such stabilizers (and/or dye enhancers) have been used in commercial spandex yarns for many years. Pigments, such as particles of titanium dioxide, also have long been used as whiteners for such fibers. However, the present inventor noted that dry spinning of spandex fibers from polymer solutions in which either the Hunt stabilizer or the TiO.sub.2 was included alone resulted in easier processing and higher yields of satisfactory product than when both the stabilizer and the TiO.sub.2 were included together. Accordingly, an object of this invention is to provide an improved process for dry-spinning spandex fibers that contain as additives, both, TiO.sub.2 particles and a polymeric tertiary amine stabilizer.